Temperature controlled substrate support assembly

ABSTRACT

Implementations described herein provide a substrate support assembly which enables both lateral and azimuthal tuning of the heat transfer between an electrostatic chuck and a heater assembly. The substrate support assembly comprises an upper surface and a lower surface; one or more main resistive heaters disposed in the substrate support; and a plurality of heaters in column with the main resistive heaters and disposed in the substrate support. A quantity of the heaters is an order of magnitude greater than a quantity of the main resistive heaters and the heaters are independently controllable relative to each other as well as the main resistive heater.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 14/285,606 filed on May 22, 2014 which claimsbenefit of U.S. Provisional Application Ser. No. 61/937,348, filed Feb.7, 2014, each of which are herein incorporated by reference in itsentirety.

BACKGROUND Field

Implementations described herein generally relate to semiconductormanufacturing and more particularly to temperature controlled substratesupport assembly and method of using the same.

Description of the Related Art

As the feature size of the device patterns get smaller, the criticaldimension (CD) requirements of these features become a more importantcriterion for stable and repeatable device performance. Allowable CDvariation across a substrate processed within a processing chamber isdifficult to achieve due to chamber asymmetries such as chamber andsubstrate temperature, flow conductance, and RF fields.

In processes utilizing an electrostatic chuck, uniformity of temperaturecontrol across the surface of the substrate is even more challenging dueto the non-homogeneous construction of the chuck below the substrate.For example, some regions of the electrostatic chuck have gas holes,while other regions have lift pin holes that are laterally offset fromthe gas holes. Still other regions have chucking electrodes, while otherregions have heater electrodes that are laterally offset from thechucking electrodes. Since the structure of the electrostatic chuck canvary both laterally and azimuthally, uniformity of heat transfer betweenthe chuck and substrate is complicated and very difficult to obtain,resulting in local hot and cold spots across the chuck surface, whichconsequently result in non-uniformity of processing results along thesurface of the substrate.

The lateral and azimuthal uniformity of heat transfer between the chuckand substrate is further complicated by heat transfer schemes commonlyutilized in conventional substrate supports to which the electrostaticchuck is mounted. For example, conventional substrate supports typicallyhave only edge to center temperature control. Thus, local hot and coldspots within the electrostatic chuck cannot be compensated for whileutilizing the heat transfer features of the conventional substratesupports.

Thus, there is a need for an improved substrate support assembly.

SUMMARY

Implementations described herein provide a substrate support assemblywhich enables both lateral and azimuthal tuning of the heat transferbetween an electrostatic chuck and a heater assembly. The substratesupport assembly comprises an upper surface and a lower surface; one ormore main resistive heaters disposed in the substrate support; and aplurality of heaters in column with the main resistive heaters anddisposed in the substrate support. A quantity of the heaters is an orderof magnitude greater than a quantity of the main resistive heaters andthe heaters are independently controllable relative to each other aswell as the main resistive heater.

In one embodiment, a substrate support assembly comprises a substratesupport having a substrate support surface and a lower surface; aplurality of resistive heaters coupled to or disposed in the substratesupport, the plurality of resistive heaters independently controllablerelative to each other; and a heater controller coupled to the pluralityof resistive heaters, wherein the heater controller includes an opticsand heater controller.

In yet another embodiment, a processing chamber comprises a chamber bodyand a substrate support assembly. The substrate support assemblycomprises an upper surface and a lower surface; one or more mainresistive heaters disposed in the substrate support; and a plurality ofheaters in column with the main resistive heaters and disposed in thesubstrate support. A quantity of the heaters is an order of magnitudegreater than a quantity of the main resistive heaters and the heatersare independently controllable relative to each other as well as themain resistive heater.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toimplementations, some of which are illustrated in the appended drawings.It is to be noted, however, that the appended drawings illustrate onlytypical implementations of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective implementations.

FIG. 1 is a cross-sectional schematic side view of a processing chamberhaving one embodiment of a substrate support assembly;

FIG. 2 is a partial cross-sectional schematic side view detailingportions of the substrate support assembly;

FIG. 3A is a cross-sectional view taken along a section line A-A of FIG.2;

FIGS. 3B-3D are cross-sectional views taken along the section line A-Aof FIG. 2, illustrating alternative layouts for heaters;

FIG. 4A-4E are partial schematic side views of illustrating variouslocations for heaters and main resistive heaters within a substratesupport;

FIG. 5 is a flow diagram of one embodiment of a method for processing asubstrate utilizing a substrate support assembly;

FIG. 6 is a simplified wiring schematic for operating heaters;

FIG. 7 is a graphical depiction for wiring of the main resistive heaterswith a hardware key;

FIG. 8 is a top plan view of a facility plate, configured to use thehardware keys;

FIG. 9 is a graphical depiction for an alternate wiring schema for themain resistive heaters without the hardware key; and

FIG. 10 is a top plan view of a cooling base, configured for the wiringschema depicted in FIG. 9.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneimplementation may be beneficially used in other implementations withoutspecific recitation.

DETAILED DESCRIPTION

Implementations described herein provide a substrate support assemblywhich enables both lateral and azimuthal tuning of the temperature of anelectrostatic chuck comprising the substrate support assembly, which inturn, allows both lateral and azimuthal tuning of the lateraltemperature profile of a substrate processed on the substrate supportassembly. Moreover, the substrate support assembly also enables localhot or cold spots on the substrate to be substantially eliminated.Methods for tuning of a lateral temperature profile a substrateprocessed on a substrate support assembly are also described herein.Although the substrate support assembly is described below in an etchprocessing chamber, the substrate support assembly may be utilized inother types of plasma processing chambers, such as physical vapordeposition chambers, chemical vapor deposition chambers, ionimplantation chambers, among others, and other systems where azimuthaltuning of a lateral temperature profile is desirable. It is alsocontemplated that the heaters may also be utilized to control thetemperature of other surfaces, including those not used forsemiconductor processing.

In one or more embodiments, the substrate support assembly allows forthe correction of critical dimension (CD) variation at the edge of thesubstrate during vacuum process, such as etching, deposition,implantation and the like, by allowing the substrate temperature to beutilized to compensate for chamber non-uniformities, such astemperature, flow conductance, electrical fields, plasma density and thelike. Additionally, some embodiments have demonstrated the ability tocontrol the temperature uniformity across the substrate to less thanabout ±0.3 degrees Celsius.

FIG. 1 is a cross-sectional schematic view of an exemplary etchprocessing chamber 100 having a substrate support assembly 126. Asdiscussed above, the substrate support assembly 126 may be utilized inother processing chamber, for example plasma treatment chambers,annealing chambers, physical vapor deposition chambers, chemical vapordeposition chambers, and ion implantation chambers, among others, aswell as other systems where the ability to control a temperature profileof a surface or workpiece, such as a substrate, is desirable.Independent and local control of the temperature across many discreteregions across a surface beneficially enables azimuthal tuning of thetemperature profile, center to edge tuning of the temperature profile,and reduction of local temperature asperities, such as hot and coolspots.

The processing chamber 100 includes a grounded chamber body 102. Thechamber body 102 includes walls 104, a bottom 106 and a lid 108 whichenclose an internal volume 124. The substrate support assembly 126 isdisposed in the internal volume 124 and supports a substrate 134 thereonduring processing.

The walls 104 of the processing chamber 100 include an opening (notshown) through which the substrate 134 may be robotically transferredinto and out of the internal volume 124. A pumping port 110 is formed inone of the walls 104 or the bottom 106 of the chamber body 102 and isfluidly connected to a pumping system (not shown). The pumping system isutilized to maintain a vacuum environment within the internal volume 124of the processing chamber 100, while removing processing byproducts.

A gas panel 112 provides process and/or other gases to the internalvolume 124 of the processing chamber 100 through one or more inlet ports114 formed through at least one of the lid 108 or walls 104 of thechamber body 102. The process gas provided by the gas panel 112 areenergized within the internal volume 124 to form a plasma 122 utilizedto process the substrate 134 disposed on the substrate support assembly126. The process gases may be energized by RF power inductively coupledto the process gases from a plasma applicator 120 positioned outside thechamber body 102. In the embodiment depicted in FIG. 1, the plasmaapplicator 120 is a pair of coaxial coils coupled through a matchingcircuit 118 to an RF power source 116.

A controller 148 is coupled to the processing chamber 100 to controloperation of the processing chamber 100 and processing of the substrate134. The controller 148 may be one of any form of general-purpose dataprocessing system that can be used in an industrial setting forcontrolling the various subprocessors and subcontrollers. Generally, thecontroller 148 includes a central processing unit (CPU) 172 incommunication with memory 174 and input/output (I/O) circuitry 176,among other common components. Software commands executed by the CPU ofthe controller 148, cause the processing chamber to, for example,introduce an etchant gas mixture (i.e., processing gas) into theinternal volume 124, form the plasma 122 from the processing gas byapplication of RF power from the plasma applicator 120, and etch a layerof material on the substrate 134.

The substrate support assembly 126 generally includes at least asubstrate support 132. The substrate support 132 may be a vacuum chuck,an electrostatic chuck, a susceptor, or other workpiece support surface.In the embodiment of FIG. 1, the substrate support 132 is anelectrostatic chuck and will be described hereinafter as theelectrostatic chuck 132. The substrate support assembly 126 mayadditionally include a heater assembly 170. The substrate supportassembly 126 may also include a cooling base 130. The cooling base mayalternately be separate from the substrate support assembly 126. Thesubstrate support assembly 126 may be removably coupled to a supportpedestal 125. The support pedestal 125, which may include a pedestalbase 128 and a facility plate 180, is mounted to the chamber body 102.The substrate support assembly 126 may be periodically removed from thesupport pedestal 125 to allow for refurbishment of one or morecomponents of the substrate support assembly 126.

The facility plate 180 is configured to accommodate a plurality ofdriving mechanism configured to raise and lower a plurality of liftingpins. Additionally, the facility plate 180 is configured to accommodatethe plurality of fluid connections from the electrostatic chuck 132 andthe cooling base 130. The facility plate 180 is also configured toaccommodate the plurality of electrical connections from theelectrostatic chuck 132 and the heater assembly 170. The myriad ofconnections may run externally or internally of the substrate supportassembly 126 while the facility plate 180 provides an interface for theconnections to a respective terminus.

The electrostatic chuck 132 has a mounting surface 131 and a workpiecesurface 133 opposite the mounting surface 131. The electrostatic chuck132 generally includes a chucking electrode 136 embedded in a dielectricbody 150. The chucking electrode 136 may be configured as a mono polaror bipolar electrode, or other suitable arrangement. The chuckingelectrode 136 is coupled through an RF filter 182 to a chucking powersource 138 which provides a RF or DC power to electrostatically securethe substrate 134 to the upper surface of the dielectric body 150. TheRF filter 182 prevents RF power utilized to form a plasma 122 within theprocessing chamber 100 from damaging electrical equipment or presentingan electrical hazard outside the chamber. The dielectric body 150 may befabricated from a ceramic material, such as AlN or Al₂O₃. Alternately,the dielectric body 150 may be fabricated from a polymer, such aspolyimide, polyetheretherketone, polyaryletherketone and the like.

The workpiece surface 133 of the electrostatic chuck 132 may include gaspassages (not shown) for providing backside heat transfer gas to theinterstitial space defined between the substrate 134 and the workpiecesurface 133 of the electrostatic chuck 132. The electrostatic chuck 132may also include lift pin holes for accommodating lift pins (both notshown) for elevating the substrate 134 above the workpiece surface 133of the electrostatic chuck 132 to facilitate robotic transfer into andout of the processing chamber 100.

The temperature controlled cooling base 130 is coupled to a heattransfer fluid source 144. The heat transfer fluid source 144 provides aheat transfer fluid, such as a liquid, gas or combination thereof, whichis circulated through one or more conduits 160 disposed in the base 130.The fluid flowing through neighboring conduits 160 may be isolated toenable local control of the heat transfer between the electrostaticchuck 132 and different regions of the cooling base 130, which assistsin controlling the lateral temperature profile of the substrate 134.

A fluid distributor may be fluidly coupled between an outlet of the heattransfer fluid source 144 and the temperature controlled cooling base130. The fluid distributor operates to control the amount of heattransfer fluid provided to the conduits 160. The fluid distributor maybe disposed outside of the processing chamber 100, within the substratesupport assembly 126, within the pedestal base 128 or other suitablelocation.

The heater assembly 170 may include one or more main resistive heaters154 and/or a plurality of heaters 140 embedded in a body 152. The mainresistive heaters 154 may be provided to elevate the temperature of thesubstrate support assembly 126 to a temperature for conducting chamberprocesses. The heaters 140 provide localized adjustments to thetemperature profile of the substrate support assembly 126 generated bythe main resistive heaters 154. Thus, the main resistive heaters 154operate on a globalized macro scale while the heaters operate on alocalized micro scale. The main resistive heaters 154 are coupledthrough an RF filter 184 to a main heater power source 156. The powersource 156 may provide 500 watts or more power to the main resistiveheaters 154. The controller 148 may control the operation of the mainheater power source 156, which is generally set to heat the substrate134 to about predefined temperature. In one embodiment, the mainresistive heaters 154 include a plurality of laterally separated heatingzones, wherein the controller 148 enables one zone of the main resistiveheaters 154 to be preferentially heated relative to the main resistiveheaters 154 located in one or more of the other zones. For example, themain resistive heaters 154 may be arranged concentrically in a pluralityof separated heating zones.

The heaters 140 are coupled through an RF filter 186 to a heater powersource 142. The heater power source 142 may provide 10 watts or lesspower to the heaters 140. In one embodiment, the power supplied by theheater power source 142 is an order of magnitude less than the powersupplied by the power source 156 of the main resistive heaters. Theheaters 140 may additionally be coupled to a controller 202. Thecontroller 202 may be located within or external to the substratesupport assembly 126. The controller 202 may manage the power providedfrom heater power source 142 to individual or groups of heaters 140 inorder to control the heat generated locally at each heaters 140distributed laterally across the substrate support assembly 126. Anoptical power source 178 may couple the controller 202 to the controller148 to decouple the controller 148 from influence of the RF energy withthe processing chamber 100.

Alternately, the one or more main resistive heaters 154, and/or theheaters 140, may be formed in the electrostatic chuck 132. In anembodiment where both the main resistive heaters 154 and the heaters 140are formed in the electrostatic chuck 132, the substrate supportassembly 126 may be formed without the heater assembly 170 and theelectrostatic chuck 132 may be disposed directly on the cooling base130.

The electrostatic chuck 132 may include one or more thermocouples (notshown) for providing temperature feedback information to the controller148 for controlling the power applied by the main heater power source156 to the main resistive heaters 154, for controlling the operations ofthe cooling base 130, and controlling the power applied by the heaterpower source 142 to the heaters 140.

The temperature of the surface for the substrate 134 in the processingchamber 100 may be influenced by the evacuation of the process gasses bythe pump, the slit valve door, the plasma 122 and other factors. Thecooling base 130, the one or more main resistive heaters 154, and theheaters 140 all help to control the surface temperature of the substrate134.

In a two zone configuration of main resistive heaters 154, the mainresistive heaters 154 may be used to heat the substrate 134 to atemperature suitable for processing with a variation of about +/−10degrees Celsius from one zone to another. In a four zone assembly forthe main resistive heaters 154, the main resistive heaters 154 may beused to heat the substrate 134 to a temperature suitable for processingwith a variation of about +/−1.5 degrees Celsius within a particularzone. Each zone may vary from adjacent zones from about 0 degreesCelsius to about 20 degrees Celsius depending on process conditions andparameters. However, the requirement for minimizing variations in thecritical dimensions across a substrate has reduced the acceptablevariation in a determined process temperature of the surface of thesubstrate surface. A half a degree variation of the surface temperaturefor the substrate 134 may result in as much as a nanometer difference inthe formation of structures therein. The heaters 140 improve thetemperature profile of the surface of the substrate 134 produced by themain resistive heaters 154 by reducing variations in the temperatureprofile to about +/−0.3 degrees Celsius. The temperature profile may bemade uniform or to precisely vary in a predetermined manner acrossregions of the substrate 134 through the use of the heaters 140 toenable realization of desired results.

FIG. 2 is a partial cross-sectional schematic view illustrating portionsof the substrate support assembly 126. Included in FIG. 2 are portionsof the electrostatic chuck 132, the heater assembly 170 and the facilityplate 180.

The body 152 of the heater assembly 170 may be fabricated from a polymersuch as a polyimide. The body 152 may generally be cylindrical in planform, but may also be formed in other geometrical shapes. The body 152has an upper surface 270 and a lower surface 272. The upper surface 270faces the electrostatic chuck 132, while the lower surface 272 faces thecooling base 130.

The body 152 of the heater assembly 170 may be formed from two or moredielectric layers (shown in FIG. 2 as three dielectric layers 260, 262,264) and heating the layers 260, 262, 264 under pressure to form asingle body 152. For example, the body 152 may be formed from polyimidelayers 260, 262, 264, which separate the main resistive heaters andheaters 154, 140, which are heated under pressure to form the singlebody 152 of the heater assembly 170. The heaters 140 may be placed in,on or between the first, second or third layers 260, 262, 264 prior toforming the body 152. Additionally, the main resistive heaters 154 maybe placed in, on or between on the first, second or third layers 260,262, 264 prior to assembly, with at least one of the layers 260, 262,264 separating and electrically insulating the heaters 154, 140. In thismanner, the heaters 140 and the main resistive heaters 154 become anintegral part of the heater assembly 170.

Alternate configurations for locations of the main resistive heaters 154and the heaters 140 may place one or both heaters 154, 140 in or underthe electrostatic chuck 132. FIGS. 4A-4E are partial schematic views ofthe substrate support assembly 126 detailing various locations for theheaters 140 and the main resistive heaters 154, although not limiting toall embodiments.

In the embodiment depicted in FIG. 4A, the substrate support assembly126 does not have a heater assembly (170) and the heaters 140 and themain resistive heaters 154 are disposed in the electrostatic chuck 132,for example, below the chucking electrode 136. Although the heaters 140are shown below the main resistive heaters 154, the heaters 140 may bealternatively positioned above the main resistive heaters 154. In theembodiment depicted in FIG. 4B, the heater assembly 170 for thesubstrate support assembly 126 includes the heaters 140 while the mainresistive heaters 154 are disposed in the electrostatic chuck 132, forexample, below the chucking electrode 136. Alternatively, the heaters140 may be disposed in the electrostatic chuck 132 while the mainresistive heaters 154 are disposed in the heater assembly 170. In theembodiment depicted in FIG. 4C, the heater assembly 170 for thesubstrate support assembly 126 has the main resistive heaters 154disposed therein. The heaters 140 are disposed in the electrostaticchuck 132, for example, below the chucking electrode 136. In theembodiment depicted in FIG. 4D, the heater assembly 170 for thesubstrate support assembly 126 has heaters 140 disposed therein whilethe main resistive heaters 154 are disposed on one of the heaterassembly 170 or the electrostatic chuck 132. The heater assembly 170isolates the heaters 140 from the cooling base 130. In the embodimentdepicted in FIG. 4E, the heater assembly 170 of the substrate supportassembly 126 has main resistive heaters 154 disposed therein. Theheaters 140 are disposed in or on the heater assembly 170, for example,below the electrostatic chuck 132. It is contemplated that the heaters140 and the main resistive heaters 154 may be arranged in otherorientations. For example, the substrate support assembly 126 may onlyhave the plurality of heaters 140 for heating the substrate 134. In oneembodiment, the heaters 140 and the main resistive heaters 154 aredisposed directly under each other within substrate support assembly126. The heaters 140 provide fine tune control for the temperatureprofile of the substrate 134 supported by the substrate support assembly126.

The heaters 140 may be formed or disposed on or in the body 152 of theheater assembly 170 or electrostatic chuck 132. The heaters 140 may beformed by plating, ink jet printing, screen printing, physical vapordeposition, stamping, wire mesh or other suitable manner. In this mannerfabrication of the substrate support assembly 126 is simplified. In oneembodiment, the heaters 140 are disposed within the heater assembly 170while forming the heater assembly 170. In another embodiment, theheaters 140 are directly disposed on the mounting surface 131 of theelectrostatic chuck 132. For example, the heaters 140 may be in a sheetform which can be adhered to the mounting surface 131 of theelectrostatic chuck 132, or the heaters may be deposited by other means.For example, the heaters 140 can be deposited on the mounting surface131 by physical vapor deposition, chemical vapor deposition, screenprinting or other suitable methods. The main resistive heaters 154 canbe in the electrostatic chuck 132 or heater assembly 170 as shown above.

The main resistive heaters 154 may be formed or disposed on or in thebody 152 of the heater assembly 170 or electrostatic chuck 132. The mainresistive heaters 154 may be formed by plating, ink jet printing, screenprinting, physical vapor deposition, stamping, wire mesh or othersuitable manner. In this manner fabrication of the substrate supportassembly 126 is simplified. In one embodiment, main resistive heaters154 are disposed within the heater assembly 170 while forming the heaterassembly 170. In another embodiment, main resistive heaters 154 aredirectly disposed on the mounting surface 131 of the electrostatic chuck132. For example, main resistive heaters 154 may be in a sheet formwhich can be adhered to the mounting surface 131 of the electrostaticchuck 132, or main resistive heaters 154 may be deposited by othermeans. For example, main resistive heaters 154 can be deposited on themounting surface 131 by physical vapor deposition, chemical vapordeposition, screen printing or other suitable methods. The heaters 140can be in the electrostatic chuck 132 or heater as shown above.

In some embodiments, the main resistive heaters 154 may be fabricatedsimilar to the heaters 140, and in such embodiments, may optionally beutilized without benefit of additional heaters 140. In other words, themain resistive heaters 154 of the substrate support assembly 126 are,that is, segmented in to a plurality of discrete resistive heatingelements. Segmenting the main resistive heaters 154 in the form of smallresistive heaters allows local control of hot and cold spots on thesurface of the substrate 134. An additional layer of heaters 140 isoptional, depending on the desired level of temperature control.

FIG. 7 is a graphical depiction for a wiring layout for a segmented mainresistive heaters 154 formed from a plurality of unit heaters 846. Theunit heaters 846 may be controlled through use of the controller 202 asdescribed above, or through the use of a heater controller in the formof a hardware wiring key 802 as depicted in FIGS. 7. One implementationfor using hardware wiring keys 802 is illustrated in a top plan view ofthe facility plate 180 shown in FIG. 8.

Referring jointly to FIGS. 7 and 8, the substrate support assembly 126may have one or more main resistive heater 154, illustratively shown asfour main resistive heaters 154, each defining one of four zones 810,820, 830, 840. The temperature in each zone 810, 820, 830, 840 may beindependently controlled by the main resistive heater 154 associatedwith zone. Additionally, each main resistive heaters 154 is comprised ofa plurality of separated unit heaters 846. The unit heaters 846 may beeither active (active unit heaters 842) or inactive (inactive unitheaters 844). Active unit heaters 842 are coupled to a power source andcontribute heat to the main resistive heaters 154. The inactive unitheaters 844 are a power source and thus, do not contribute heat to themain resistive heaters 154. Thus, by selectively choosing which mainresistive heaters 154 are active unit heaters 842 or inactive unitheaters 844, the temperature profile of the substrate support assembly126 may be controlled, for example, to control local hot or cold spots,to provide center to edge tuning of the temperature profile, and toprovide azimuthal tuning of the lateral temperature profile of thesubstrate support assembly 126, and consequently, the substrate 134processed thereon.

The unit heaters 846 for each main resistive heater 154 may be selectedto form a pattern of active heater density within each of the zones 810,820, 830, 840. The pattern of the unit heaters 846 may be tightly packedand uniform, similar to the pattern of unit heaters labeled 854.Alternately, the pattern for the unit heaters 846 may be loosely spaced.The unit heaters 846 may be switched between active unit heaters 842 andinactive unit heaters 844 using hardware, such as the hardware wiringkey 802, the controller 202, software or firmware executed by controller148, or through another method or device. Thus, the temperature profilegenerated from the main resistive heaters 154 in each of the zones 810,820, 830, 840 may be refined by selectively activating the unit heaters846 to control the heat supplied by the main resistive heaters 154.

Each unit heater 846, that is all active unit heaters 842 and allinactive unit heaters 844, has a wired connection 860. The wiredconnections 860 are routed to a receptacle 804, for example, formed inthe facility plate 180. In one embodiment, the wired connections 860 mayextend outward of the substrate support assembly 126 and run down theoutside of the substrate support assembly 126 to the receptacle 804 inthe facility plate 180. Alternately, the wired connection 860 may runinternally through the heater assembly 170, for example, through a holein the cooling base 130 to the receptacle 804 in facility plate 180.

The receptacle 804 in the facility plate 180 has an interior surface 805and a side surface 806. The wired connections 860 may terminate at theinterior surface 805, thus forming a connector or socket. A controlboard connection 868 may terminate at the side surface 806 with aconnector or socket. The control board connection 868 may be a singlepower lead or a plurality of power leads. The wired connections 860 andthe control board connections 868 are part of a circuit. Alternately,the wired connections 860 and the control board connections 868 may bothresiding on the same surface of the facility plate 180. For example,both the wired connections 860 and the control board connections 868 mayreside on an interior surface 805 of the receptacle 804. A gap in thecircuit is formed at the receptacle 804 such that no current may flowacross the circuit, i.e. from the control board connections 868 to thewired connections 860.

The hardware wiring key 802 is configured to fit in the receptacle 804.The hardware wiring key 802 may be flush with outer surface 880 of thefacility plate 180 while a front surface 866 of the hardware wiring key802 makes contact with the interior surface 805 of the receptacle 804.Additionally, the side surface 886 of the hardware wiring key 802 is incontact the side surface 806 of the receptacle. The hardware wiring key802 is configured to selectively fill the gap in the circuit at thereceptacle 804 such that current may flow from the control boardconnections 868 to selected wired connections 860. In this manner theelectrical connections between the wired connections 860 and the controlboard connections 868 can be made. Thus, the hardware wiring key 802 isconfigured to selectively provide power to the unit heaters 846.

The hardware wiring key 802 may use a common negative terminal for eachof the wired connections 860. For instance, all the negative terminalsmay utilize a common bus that may be formed in the jacket of thehardware wiring key 802 or the negative terminal may be a shared pinconnection. Alternately, the hardware wiring key 802 may use individualnegative terminal for each of the wired connections 860. The negativeterminal may have a gate switch or other means for selectivelyinterrupting the flow of current across the terminal.

The hardware wiring key 802 may be formed in a manner to preselect onlythose circuits which are desired to make active and available to deliverpower to the unit heaters 846. The inactive circuits may have gaps orgates 864, unformed circuitry within the hardware wiring key 802, or aninsulating cap (not shown), among other suitable means for interruptingthe flow of power to the wired connections 860 of the unit heaters 846within the main resistive heaters 154. Thus, one hardware wiring key 802may be utilized to provide a predefined lateral temperature distributionof the substrate while performing one process, and replaced by ahardware wiring key 802 having a different preselection of circuitswhich are desired to make active are available to deliver power to theunit heaters 846 which will yield a different predefined lateraltemperature distribution of the substrate while performing anotherprocess. In this manner, different hardware wiring keys 802 may beefficiently swapped out to provide different temperature profiles, andaccordingly, greater flexibility in ensuring realization of beneficialprocessing results.

The wired connections 860 may be divided and equally spaced about theouter surface 880 of the facility plate 180. In one embodiment, thefacility plate has four receptacles 804, each receptacle having asubstantially equal number of wired connections 860. This arrangementallows the substrate support assembly 126 to be symmetrically balancedand minimizes the effects of the wiring on processes occurring withinthe processing chamber 100. Advantageously, the arrangement of unitheaters 846 and connections provide a homogenous construction for thesubstrate support assembly 126, and promotes process symmetry.

The unit heaters 846, of the main resistive heaters 154, allow the mainresistive heaters 154 to have a temperature range between about ambientto about 500 degrees Celsius with the ability to control the lateraltemperature profiled in increments of about 0.3 degrees Celsius. Thesubstrate support assembly 126, having main resistive heaters 154configured with unit heaters 846, has demonstrated the ability tocontrol the temperature uniformity of a substrate processed thereon toless than about ±1.5 degrees Celsius.

Returning back to the embodiment depicted in FIG. 2, the heater assembly170 may be coupled to the mounting surface 131 of the electrostaticchuck 132 utilizing a bonding agent 244. The bonding agent 244 may be anadhesive, such as an acrylic-based adhesive, an epoxy, a silicon basedadhesive, a neoprene-based adhesive or other suitable adhesive. In oneembodiment, the bonding agent 244 is an epoxy. The bonding agent 244 mayhave a coefficient of thermal conductivity selected in a range from 0.01to 200 W/mK and, in one exemplary embodiment, in a range from 0.1 to 10W/mK. The adhesive materials comprising the bonding agent 244 mayadditionally include at least one thermally conductive ceramic filler,e.g., aluminum oxide (Al₂O₃), aluminum nitride (AlN), and titaniumdiboride (TiB₂), and the like.

In one embodiment, the heater assembly 170 is coupled to the coolingbase 130 utilizing a bonding agent 242. The bonding agent 242 may besimilar to the bonding agent 244 and may be an adhesive, such as anacrylic-based adhesive, an epoxy, a neoprene-based adhesive or othersuitable adhesive. In one embodiment, the bonding agent 242 is an epoxy.The bonding agent 242 may have a coefficient of thermal conductivityselected in a range from 0.01 to 200 W/mK and, in one exemplaryembodiment, in a range from 0.1 to 10 W/mK. The adhesive materialscomprising the bonding agent 242 may additionally include at least onethermally conductive ceramic filler, e.g., aluminum oxide (Al₂O₃),aluminum nitride (AlN), and titanium diboride (TiB₂), and the like.

The bonding agents 244, 242 may be removed when refurbishing one or moreof the electrostatic chuck 132, the cooling base 130 and the heaterassembly 170. In other embodiments, the heater assembly 170 is removablycoupled to the electrostatic chuck 132 and to the cooling base 130utilizing fasteners or clamps (not shown).

The heater assembly 170 includes a plurality of heaters 140,illustratively shown as heaters 140 a, 140 b, 140 c. The heaters 140 aregenerally an enclosed volume within the heater assembly 170 in which aplurality of resistive heaters effectuate heat transfer between theheater assembly 170 and electrostatic chuck 132. Each heater 140 may belaterally arranged across the heater assembly 170, and thus defined acell 200 within the heater assembly 170 for locally providing additionalheat to region of the heater assembly 170 (and portion of the mainresistive heater 154) aligned that cell 200. The number of heaters 140formed in the heater assembly 170 may vary, and it is contemplated thatthere is at least an order of magnitude more heaters 140 (and cells 200)greater than the number of the main resistive heaters 154. In oneembodiment in which the heater assembly 170 has four main resistiveheaters 154, there may be greater than 40 heaters 140. However, it iscontemplated that there may be about 200, about 400 or even more heaters140 in a given embodiment of a substrate support assembly 126 configuredfor use with a 300 mm substrate. Exemplary distribution of the heaters140 are described further below with reference to FIGS. 3A-3D.

The cells 200 may be formed through one or more layers 260, 262, 264comprising the body 152 of the heater assembly 170. In one embodiment,the cells are open to the lower and upper surface 272, 270 of the body152. The cells may include sidewalls 214. The sidewalls 214 may becomprised of a material (or gap) acting as a thermal choke 216. Thethermal chokes 216 are formed in the upper surface 270 of the body 152.The thermal chokes 216 separate and reduce conduction between adjacentcells 200. Thus, by individually and independently controlling the powerprovided to each heaters 140, and consequently the heat transfer throughcell 200, a by approach to temperature control can be realized whichenables specific points of the substrate 134 to be heated or cooled,thereby enabling a truly addressable lateral temperature profile tuningand control of the surface of the substrate 134.

An additional thermal choke 216 may be formed between the radiallyoutermost cells 200 and a laterally outermost sidewall 280 of the body152. This outermost thermal choke 216 located between the cells 200 andthe laterally outermost sidewall 280 of the body 152 minimizes heattransfer between the cells 200, adjacent to the laterally outermostsidewall 280, and the internal volume 124 of the processing chamber 100.Thereby allowing more precise temperature control closer to the edge ofthe substrate support assembly 126, and as a result, better temperaturecontrol to the outside diameter edge of the substrate 134.

As discussed above, each heater 140 may be independently coupled acontroller 202. The controller 202 may be disposed in the substratesupport assembly 126. The controller 202 may regulate the temperature ofthe heaters 140 in the heater assembly 170 at each cell 200 relative tothe other cells 200, or alternatively, regulate the temperature of agroup of heaters 140 in the heater assembly 170 across a group of cells200 relative to the another group of cells 200. The controller 202 maytoggle the on/off state or control the duty cycle for individual orgroups of the heaters 140. Alternately, the controller 202 may controlthe amount of power delivered to the individual or groups of heaters140. For example, the controller 202 may provide one or more heaters 140ten watts of power, other heaters 140 nine watts of power, and stillother heaters one watt of power.

In one embodiment, each cell 200 may be thermally isolated from theneighboring cells 200, for example, using a thermal choke 216, whichenables more precise temperature control. In another embodiment, eachcell 200 may be thermally joined to an adjacent cell creating ananalogue (i.e., smooth or blended) temperature profile along an uppersurface 270 of the heater assembly 170. For example, a metal layer, suchas aluminum foil, may be used as a thermal spreader between the mainresistive heaters 154 and the heaters 140.

The use of independently controllable the heaters 140 to smooth out orcorrect the temperature profile generated by the main resistive heaters154 enable control of the local temperature uniformity across thesubstrate to very small tolerances, thereby enabling precise process andCD control when processing the substrate 134. Additionally, the smallsize and high density of the heaters 140 relative to the main resistiveheaters 154 enables temperature control at specific locations of thesubstrate support assembly 126, substantially without affecting thetemperature of neighboring areas, thereby allowing local hot and coolspots to be compensated for without introducing skewing or othertemperature asymmetries. The substrate support assembly 126, having aplurality of heaters 140, has demonstrated the ability to control thetemperature uniformity of a substrate 134 processed thereon to less thanabout ±0.3 degrees Celsius.

Another benefit of some embodiments of the substrate support assembly126 is the ability to prevent RF power from traveling through controlcircuitry. For example, the controller 202 may include an electricalpower circuit 210 and an optical control circuit 220. The electricalpower circuit 210 is coupled to the heaters 140. Each heater 140 has apair of power leads (connectors 250) which are connected to theelectrical power circuit 210. In an exemplary heater assembly 170 havingfifty heaters 140, 50 pairs of power leads (connectors 250) are neededfor controlling the heaters 140. The RF energy supplied into theprocessing chamber 100 for forming the plasma couples to the powerleads. Filters, such as the RF filters 182, 184, 186 shown in FIG. 1,are used to protect electrical equipment, such as the main heater powersource 156, from the RF energy. By terminating the power leads(connectors 250) at the electrical power circuit 210, and utilizing theoptical control circuit 220 to control how much power is provided toeach heaters 140, only the single RF filter 184 is needed between theelectrical power circuit 210 and the power source 156. In conventionalapplications, each heater requires a dedicated RF filter. Accordingly,as the space for dedicated RF filters very limited, the number ofheaters utilized within the substrate support assembly is also limited,thereby limiting the number of main heater zones which may be employed,and making corrective heaters impossible to implement. Thus, the use ofthe electrical power circuit 210 with the optical control circuit 220allow more heaters, and consequently, superior lateral temperaturecontrol.

Turning briefly to FIG. 6, the simplified wiring schematic for theheaters 140 illustrates the reduced number of RF filters needed toprotect electrical chamber components from the RF signal. A flex circuit600 may be utilized to assist controlling the plurality of heaters 140.The flex circuit 600 may form a matrix pattern with the heaters 140. Theflex circuit 600 may consist of a number of non-intersecting positiveleads 640 and negative leads 650, each attached at one end to thecontroller 202. Each positive lead 640 may have a plurality of heaterassemblies 662 bridging a connection to a corresponding negative lead650. Thus, the heater assembly 662 is deposed between each connection ofthe positive and negative leads 640, 650. In one exemplary embodiment,the flex circuit 600 may have 9 positive leads 640 and 9 negative leads650 and therefore as many as 81 heater assemblies 662.

The heater assembly 662 has a heater 663 and a diode 664 connected inseries. The heater 663 attaches to the positive lead 640 and the diode664 may attach to the negative lead 650. Alternately, heater 663attaches to the negative lead 650 and the diode 630 may attach to thepositive lead 640. The diode 664 ensures current flows only in onedirection. In one embodiment, the direction of the current flow for eachof the heater assemblies 662 is from the positive lead 640 to thenegative lead 650.

The controller 202 may open and/or close individual circuits to providea predetermined current flow across a selection of the positive leads640 and the negative leads 650. For example, the controller 202 mayprovide for current flow on positive lead labeled 641 and a return flowfor the current on negative lead labeled 653, with all other positiveand negative leads 640, 650 acting as open circuits. Alternately, thecontroller 202 may selectively provide for current flow on positiveleads labeled 642 and 643 while providing for a return flow on anegative lead 652, with all other positive and negative leads 640, 650acting as open circuits. The controller 202 may therefore selectivelyprovide current to the heater assemblies 662 disposed between theselected combinations of positive and negative leads 640, 650. The flexcircuit 600 completes individual circuits with the fewest number ofconnections back to the controller 202 for supplying power to eachheater 663.

In one embodiment, the controller 202 provides current on the positivelead labeled 641 and a return path for the current is provided on allthe negative leads 650. Heaters 140 along the top row 612 areselectively turned on (active) while the remaining of the heaters 140are inactive. In another embodiment, the controller 202 provides currenton the positive leads labeled 641 and 642 and provides a return path forthe current on the negative leads labeled 651 and 652. In thisconfiguration, a small group of four heaters 691, 692, 693, 694 areselectively turned on while the remaining heaters 140 remain inactive(i.e., unpowered). Thus, the controller 202 may be utilized toselectively activate various heaters 140 by activating selected thepositive leads 640 and selected the negative leads 650. The controller202 may also control the voltage across or current through a givenheater to control the amount of heat generated by a particular heater.The controller 202 may alternatively, or in addition, control the dutycycle for a given heater to control the amount of heat generated by aparticular heater over time. The controller 202 may alternatively, or inaddition, scan through the heaters to control the amount of heatgenerated by a particular heater over time.

The flex circuit 600 may be formed in, on, or below, one of the layers260, 262, 264 comprising the body 152 of the heater assembly 170. Theheaters 140 may be disposed above or in conjunction with the flexcircuit 600. The flex circuit 600 may be deposited, plated, ink jetprinted, screen printed or formed in any suitable manner. The positiveleads 640 and the negative leads 650 may form one or more connectors 250to connect the flex circuit 600 to the controller 202. The connectors250 may extend internally through the substrate support assembly 126.For example, the cooling base 130 and the facility plate 180 may haveone or more passages formed therethrough to accommodate the passage ofthe connectors 250. The connectors 250 may be divided, positioned ordistributed throughout the substrate support assembly 126 in such amanner that balances any effects of the wiring on the plasma processesongoing in the processing chamber 100. For example, four connectors 250may pass through four equally spaced passages formed about a center ofthe substrate support assembly 126. In one embodiment, the flex circuit600 may be printed on or within the layers of the heater assembly 170with a hundred or more terminal leads for operating 50 or more heaters140. In one example, four hundred terminal leads are utilized to providepower to two hundred heaters 140. The terminal leads may be divided intoseparate flexible strips, such as a ribbon cable or circuit, which maybe run through slots formed in the cooling base 130. The flexible stripscontaining the terminal lead may be run through equally spaced slotsformed through the cooling base 130 to the facility plate 180 to providesymmetrical geometry which contributes to symmetrical temperaturecontrol and process uniformity.

Returning back to FIG. 2, the electrical power circuit 210 may switch orcycle power to the plurality of connectors 250 coming from the flexcircuit 600. The electrical power circuit 210 provides power to each ofthe connectors 250 to activate one or more heaters 140. Although theelectrical power source ultimately supplies power to the plurality ofheaters 140, the electrical power circuit 210 has a single power source,i.e. the heater power source 142, and thus only requires only the singlefilter 184. Advantageously, the space and expense for additional filtersare mitigated, while enabling use of many heaters and heater zones.

The optical control circuit 220 may be coupled to the electrical powercircuit 210 by an optical cable 226, such as a fiber optic cable, tocontrol the power supplied to the connectors 250 and thus, the heaters140. The optical control circuit 220 may be coupled to an optical powersource 178 through an optical wave guide 228. The optical power source178 is coupled to the controller 148 for providing signals controllingthe function of the heaters 140. The optical cable 226 and optical waveguide 228 are not subject to electromagnetic interference or radiofrequency (RF) energy. Thus, an RF filter to protect the optical powersource 178 from RF energy in the controller 202 is unnecessary, therebyallowing more space in the substrate support assembly 126 for routingother utilities.

The optical control circuit 220 may send commands, or instruction, tothe electrical power circuit 210 for regulating each heater 140 orgroups/regions of heaters 140. As seen in the flex circuit 600 of FIG.6, a single heater 140 or groups/regions of heaters 140 may be activatedusing a minimum number of connections back to the electrical powercircuit 210 and controlled by the optical control circuit 220.

The optical control circuit 220 may be programmed and calibrated bymeasuring the temperature rise at each heater 140. The temperature risemay be associated with incremental power increases to the heaters 140.For example, the temperature rise may be associated with a percentageincrease, for example 5% increase, in the power supplied to the heater140. A temperature map may be obtained using this method. The map maycorrelate the CD or temperature to the power distribution curve for eachheater 140. Thus, the heater 140 may be used to generate a temperatureprofile on the substrate based on a program regulating power settingsfor the individual heaters 140. The logic can be placed directly in theoptical control circuit 220 or in an externally connected controller,such as the controller 148.

The arrangement of the heaters 140 will now be discussed with referenceto FIGS. 3A through 3D. FIG. 3A is a cross-sectional view of FIG. 2along a section line A-A, according to one embodiment. FIGS. 3B-3D arecross-sectional views along the same section line A-A of FIG. 2,according to alternate embodiments.

Referring now to FIG. 3A, the plurality of heaters 140 are disposedalong the plane of the cross section line A-A through the body 152 ofthe heater assembly 170. The thermal choke 216 is disposed between eachneighboring cell 200, each cell 200 associated with at least one of theheaters 140. Additionally, the thermal choke 216 is disposed along anouter surface 326 of the substrate support assembly 126. The number ofcells 200 shown are for illustration only, and any number of embodimentsmay have substantially more (or less) cells 200. The number of heaters140 may be at least an order of magnitude greater than the number ofmain resistive heaters 154. The number of heaters 140 located across thesubstrate support assembly 126 may easily be in excess of severalhundred.

Each heater 140 has a resistor 304 ending in terminals 306, 308. Ascurrent enters one terminal, such as the terminal labeled 306, and exitsthe other terminal, such as the terminal labeled 308, the currenttravels across the wire of the resistor 304 and generates heat. Theheater 140 may have a design power density to provide the appropriatetemperature rise along the outer surface 326 of the substrate supportassembly 126. The amount of heat released by the resistor 304 isproportional to the square of the current passing therethrough. Thepower design density may be between about 1 watt/cell to about 100watt/cell, such as 10 watt/cell.

The resistor 304 may be formed from a film of nichrome, rhenium,tungsten, platinum, tantalum or other suitable materials. The resistor304 may have an electrical resistivity (ρ). A low ρ indicates a materialthat readily allows the movement of an electric charge across theresistor 304. The resistance (R) is dependent on the ρ times the length(I) over the cross sectional area (A) of the wire, or simply R=ρ·I/A.Platinum has a p of about 1.06×10⁻⁷ (Ω·m) at 20° C. Tungsten has a ρ ofabout 5.60×10⁻⁸ (Ω·m) at 20° C. Nichrome has a p of about 1.1×10⁻⁸ toabout 1.5×10⁻⁸ (Ω·m) at 20° C. Of the three aforementioned materials,the resistor 304 comprised of nichrome allows the electrical charge tomove more readily, and thus, generate more heat. However, the electricalproperties for tungsten may differentiate the material as a resistiveheater in certain temperature ranges.

The resistor 304 may have a film thickness (not shown) and a wirethickness 372 configured to efficiently provide heat when a current ispassed along the resistor 304. An increase in the wire thickness 372 forthe resistor 304 may result in a decrease in the resistance R of theresistor 304. The wire thickness 372 may range from about 0.05 mm toabout 0.5 mm for a tungsten wire and about 0.5 mm to about 1 mm for anichrome wire.

Recalling the formula R=ρ·I/A, it can be seen that the material, lengthof wire, and the wire thickness may be selected for the resistor 304 tocontrol cost, power consumption, and the heat generated by each heater140. In one embodiment, a resistor 304 is comprised of tungsten having awire thickness 372 of about 0.08 mm and a resistance of about 50 Ohms at10 watts of power.

The heaters 140 may be configured in a pattern 390 to efficientlygenerate a heat profile along the surface of the substrate supportassembly 126. The pattern 390 may be symmetric about a midpoint 392while providing clearance in and around holes 322 for lift pins or othermechanical, fluid or electrical connections. Each heater 140 may becontrolled by the controller 202. The controller 202 may turn on asingle heater 140 defining a heater 340; or a plurality of heaters 140grouped to define an inner wedge 362, a perimeter group 364, a pieshaped area 360, or other desired geometric configuration, includingnon-contiguous configurations. In this manner, temperature can beprecisely controlled at independent locations along the surface of thesubstrate support assembly 126, such independent locations not limitedto concentric ring such as known in the art. Although the pattern shownis comprised of smaller units, the pattern may alternatively have largerand/or smaller units, extend to the edge, or have other forms.

FIG. 3B is a top view of the plurality of heaters 140 disposed along theplane of the cross section line AA through the body 152, according toanother embodiment. The thermal chokes 216 may optionally be present.The heaters 140 are arranged in the form of a grid, thus defining anarray of temperature control cells 200 also arranged in the gridpattern. Although the grid pattern of heaters 140 is shown as an X/Ygrid comprised of rows and columns, the grid pattern of heaters 140 mayalternatively have some other uniformly packed form, such as a hexagonclose pack. It should be appreciated, as discussed supra, the heaters140 may be activated in groups or singularly.

FIG. 3C is a top view of the plurality of heaters 140 disposed along theplane of the cross section line AA through the body 152, according toanother embodiment. FIG. 3C illustrates a plurality of heaters 140arranged in a polar array in the body 152. Optionally, one or more ofthermal chokes 216 may be disposed between the heaters 140. The polararray pattern of the heaters 140 defines the neighboring cells 200,which are thus also be arranged in a polar array. Optionally, thermalchokes 216 may be utilized to isolate adjacent cells 200 fromneighboring cells 200.

FIG. 3D is a top view of the plurality of heaters 140 disposed along theplane of the cross section line A-A through the body 152, according toanother embodiment. FIG. 3D illustrates a plurality of heaters 140arranged in the body 152 in concentric channels. The concentric channelpattern of the heaters 140 may be optionally separated by thermal chokes216. It is contemplated that the heaters 140 and cells 200 may bearranged in other orientations.

Turning briefly to FIG. 9, a graphical depiction is provided for analternate wiring schema for the main resistive heaters 154 and theheaters 140. The wiring schema does not make use of the hardware key(802 in FIG. 7). The main resistive heaters 154 and the heaters 140 maybe attached to a controller 902. The controller 902 is attached to apower source 978 through a common filter 910. Controller 902 is similarto controller 202 shown in FIGS. 1 and 2 and has a similar version ofthe electrical power circuit 210 and the optical control circuit 220.

The heaters 140 _((1-n)) are figuratively shown and should be understoodthat heater 140 ₁ may represent a large group of heaters in a commonzone, or alternatively, all the heaters 140 disposed across thesubstrate support assembly 126. There are an order of magnitude moreheaters 140 than main resistive heaters 154, and therefore, an order ofmagnitude more connections to the electrical power circuit 210 and theoptical control circuit 220.

The electrical power circuit 210 accepts a plurality of power ribbons912, 922 from both the heaters 140 and the main resistive heaters 154through a hole or slot 920 formed through the cooling base 130. Theribbons 912, 922, graphically depict a number of power leads for eachheater 140 and main resistive heater 154. For example, power ribbon 912comprises separate power leads for the heaters 140 _((1-n)). In oneembodiment, each power lead has a switch 960 which may be activated by arespective control lead. It is contemplated that a single ribbon, oreven three or more ribbons, may be utilized to route the power leads forthe heaters 140 and main resistive heater 154.

The optical control circuit 220 accepts a plurality of control ribbons940, 950 from both the heaters 140 and the main resistive heaters 154through the slot 920 formed through the cooling base 130. The ribbons940, 950 graphically depict a number of control leads for each heater140 and main resistive heater 154. For example, control ribbon 940comprises separate control leads. The optical control circuit 220 maytake input, from a program, temperature measuring device, an externalcontroller, a user or by other source, and determines which heaters 140and main resistive heaters 154 to energize. As the optical controlcircuit 220 uses optics to transmit between the input device, theswitches and electrical controller, the optical controller is notsubject to RF interference and does not propagate the same to regionsoutside of the processing chamber. It is contemplated that a singleribbon, or even three or more ribbons, may be utilized to route thecontrol leads.

The control leads 940 provide signals generated by the optical controlcircuit 220 to control the state of a switch 960. The switch 960 may bea field effect transistor, or other suitable electronic switch.Alternately, the switch 960 may be embedded in an optically controlledcircuit board in the electrical power circuit 210. The switch 960 mayprovide simple cycling for the heaters 154, 140 between an energized(active) state and a de-energized (inactive) state. Alternately, theswitch may be a variable resistor, or other suitable device, which cancontrol the amount of power supplied to the heaters 154, 140.

In one embodiment, the controller 202 provides a signal along thecontrol ribbon 940 ₁ to instruct the switch 960 ₁ to allow 50% of thepower to pass therethrough. The power power circuit 210 provides about10 watts of power along the power ribbon 912 ₁. The switch 960 ₁ allows50% of the supplied power to pass through to a heater 140 ₁ which heatsup with about 5 watts of power.

In another embodiment, the controller 202 provides a signal along thecontrol ribbon 950 ₂ to instruct the switch 960 ₂ to allow 100% of thepower to pass therethrough. The power power circuit 210 provides about100 watts of power along the power ribbon 922 ₂. The switch 960 ₂ allows100% of the supplied power to pass through to the main resistive heater154 ₂ which heats up with about 100 watts of power. Similarly, the mainresistive heaters 154 _((1-N)) may all be operated from controller 202.

In yet another embodiment, the controller 202 provides a signal alongthe control ribbon 940 to instruct the switches 960 to be in either anactive state that allows power to pass therethrough or an inactive statethat prevents power from passing therethrough. The power power circuit210 provides about 10 watts of power along the power ribbon 912 to eachheater 140 coupled to a switch 960 in the active state. The controller202 independently controls at least one of the duration that the switch960 remains in the active state and the duty cycle of each of the switch960 relative to the other switches 960, which ultimately providescontrols the temperature uniformity of the substrate support assembly126 and substrate positioned thereon. The switches 960 controlling powerto the main resistive heaters 154 may be similarly controlled.

In another embodiment, each main resistive heater 154 _((1-N)),representing a separate zone, may have a separate controller 202. Inthis embodiment, the heaters_((1-N)) common to a zone with one mainresistive heater 154 _((1-N)) may share the controller 202 with thecommon main resistive heater 154 _((1-N)). For example, if there werefour zones, there would be four main resistive heaters 154 ₍₁₋₄₎ andfour equally spaced controllers 202. FIG. 10 is a top plan view of thecooling base 130 having holes 960 configured for the wiring schema offour zones and four equally spaced controllers 202.

In other embodiments, separate controllers 202 may be utilized to splitup the number of heaters 140 serviced by a single controller. Splittingup the control of the heaters 140 allows for smaller controllers andless space required to route the ribbons through the slots 920 formedthrough the cooling base, as shown in FIG. 9.

Returning to FIG. 2, the number and density of the heaters 140contribute to the ability for controlling the temperature uniformityacross the substrate to very small tolerances which enables preciseprocess and CD control when processing the substrate 134. Additionally,individual control of one heaters 140 relative to another heaters 140enables temperature control at specific locations in the substratesupport assembly 126 without substantially affecting the temperature ofneighboring areas, thereby allowing local hot and cool spots to becompensated for without introducing skewing or other temperatureasymmetries. The heaters 140 may have an individual temperature rangebetween about 0.0 degrees Celsius and about 10.0 degrees Celsius withthe ability to control the temperature rise in increments of about 0.1degrees Celsius. In one embodiment, the plurality of heaters 140 in thesubstrate support assembly 126 in conjunction with the main resistiveheaters 154 have demonstrated the ability to control the temperatureuniformity of a substrate 134 processed thereon to less than about ±0.3degrees Celsius. Thus, the heaters 140 allow both lateral and azimuthaltuning of the lateral temperature profile of the substrate 134 processedon the substrate support assembly 126.

FIG. 5 is a flow diagram for one embodiment of a method 500 forprocessing a substrate utilizing a substrate support assembly, such asthe substrate support assembly described above, among others. The method500 begins at block 502 by applying power to a main resistive heaterformed in a substrate support assembly. The main resistive heater may bea single heater, or segmented into zones. The main resistive heaterzones may be independently controllable.

At block 504, power is provided to a plurality of heaters distributedlaterally within the substrate support assembly. At least two of theheaters generating a predetermined different amount of heat. Thedifference in heat generated by one heater relative another may becontrolled by controlling at least one or more of the duty cycle,voltage, current, duration of power applied to one heater relativeanother. The power may also be sequentially scanned across heaters.

Control of the power provided to the heaters may be provide through anoptical signal interfacing with a controller disposed in the substratesupport assembly.

At block 506, a workpiece, such as a substrate, may be processed on thesubstrate support assembly. For example, the substrate may be processedin a vacuum chamber, for example using a plasma process. The vacuumprocess, which may be optionally performed in the presence of a plasmawithin the processing chamber, may be one of etching, chemical vapordeposition, physical vapor deposition, ion implantation, plasmatreating, annealing, oxide removal, abatement or other plasma process.It is contemplated that the workpiece may be processed on thetemperature controlled surface in other environments, for example, atatmospheric conditions, for other applications.

Optionally, at block 506, power provided to the plurality of heatersdistributed laterally within the substrate support assembly may bechanged in response to process conditions or a change in a processrecipe. For example, the power provided to the plurality of heaters maybe changed utilizing commands from the controller 202, or changing onehardware wiring key 802 to a different hardware wiring key 802.

In addition to the examples described above, some additionalnon-limiting examples may be described as follows.

-   Example 1. A processing chamber comprising:

chamber body;

a substrate support assembly, comprising:

an upper surface and a lower surface;

one or more main resistive heaters disposed in the substrate supportassembly; and

a plurality of heaters in column with the main resistive heaters anddisposed in the substrate support, wherein a quantity of the heaters isan order of magnitude greater than a quantity of the main resistiveheaters and the heaters are independently controllable relative to eachother as well as the main resistive heaters.

-   Example 2. The processing chamber of example 1, wherein the    substrate support is an electrostatic chuck.-   Example 3. The processing chamber of example 1, wherein    electrostatic chuck has a ceramic body.-   Example 4. The processing chamber of example 3, wherein at least one    of the main resistive heaters and the plurality of heaters are    formed on the lower surface of the ceramic body.-   Example 5. The processing chamber of example 3, wherein at least one    of the main resistive heaters and the plurality of heaters are    disposed in a polymer body coupled to the lower surface of the    ceramic body.-   Example 6. The processing chamber of example 1, further comprising:

a cooling plate coupled to the substrate support.

-   Example 7. The processing chamber of example 6, further comprising:

a heater controller for regulating a temperature output for each heateris coupled to the cooling plate.

-   Example 8. The processing chamber of example 7, wherein the heater    controller includes a fiber optics control circuit and an electrical    power control.-   Example 9. A substrate support assembly, comprising:

a substrate support having a substrate support surface and a lowersurface;

a plurality of resistive heaters disposed across the substrate support,the plurality of resistive heaters grouped into concentric zones; and

a heater controller coupled each group of resistive heaters, the heatercontroller operable to control which resistive heater within a givenzone generates more heat than other resistive heaters within the givenzone.

-   Example 10. The processing chamber of example 9, wherein the heater    controller comprises:

a fiber optics control circuit and an electrical power control.

-   Example 11. The processing chamber of example 9, wherein the heater    controller comprises:

one or more hardware wiring keys.

While the foregoing is directed to implementations of the presentinvention, other and further implementations of the invention may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

We claim:
 1. An electrostatic chuck (ESC), comprising: a dielectric bodyformed from ceramic material, the dielectric body comprising: an uppersurface and a lower surface, a chucking electrode disposed in thedielectric body, one or more main resistive heaters disposed in thedielectric body, and a plurality of secondary heaters in the dielectricbody between the main resistive heaters and one of the upper surface andthe lower surface, wherein a quantity of the secondary heaters isgreater than a quantity of the main resistive heaters, each secondaryheater coupled to a unique power circuit with the dielectric body, eachpower circuit configured to independently operate the connectedsecondary heater between an on state and an off state without changingthe on state and off state of any of the other secondary heaters as wellas the one or more main resistive heaters.
 2. The ESC of claim 1,wherein the plurality of secondary heaters are concentrically arrangedabout a center of the dielectric body into groups of secondary heatersalong a common radius.
 3. The ESC of claim 1 wherein any one powercircuit enables it coupled secondary heater to remain in the off stateall other secondary heaters are simultaneously switched to the on state.4. The ESC of claim 1, further comprising: a plurality of switches, eachsecondary heater coupled to a respective switch providing individualcontrol for each secondary heater; and a plurality of control leads,each control lead coupled to a respective individual switch of theplurality of switches and each control lead configured to control oneand only one individual secondary heater of the plurality of secondaryheaters.
 5. The ESC of claim 4, wherein each individual switch isconfigured to be individually and directly coupled to a power source. 6.The ESC of claim 4, wherein the switch is disposed on a negativeterminal of each secondary heaters selectively interrupting the flow ofcurrent across the terminal.
 7. The ESC of claim 4, wherein the switchis operable to allow 50% of the power to pass through to a respectiveone of each secondary heater.
 8. The ESC of claim 1, wherein thechucking electrode is disposed between the plurality of secondaryheaters and the upper surface.
 9. A substrate support assembly,comprising: a substrate support having a dielectric body, the dielectricbody comprising: a substrate support surface and a lower surface; a mainresistive heater coupled to or disposed in the dielectric body; and aplurality of resistive secondary heaters disposed in the dielectricbody, each of the plurality of resistive secondary heaters isindependently controllable relative to all other resistive secondaryheaters and the main resistive heater, wherein the plurality ofresistive secondary heaters are configured to be individually switchedby a respective state switch to enable each combination of individualstate switches to independently power each combination of resistivesecondary heaters relative to a quantity of all other resistivesecondary heaters, the quantity being greater than or equal to
 2. 10.The substrate support assembly of claim 9, wherein each individual stateswitch has a control lead configured to individually and directlycoupled to a controller.
 11. The substrate support assembly of claim 9,wherein the substrate support is an electrostatic chuck and thedielectric body of the electrostatic chuck is ceramic.
 12. The substratesupport assembly of claim 9, wherein the plurality of resistivesecondary heaters are concentrically arranged in groups of resistivesecondary heaters along a common radius.
 13. The substrate supportassembly of claim 12, wherein the main resistive heater is formed on thelower surface of the dielectric body.
 14. The substrate support assemblyof claim 12, wherein the main resistive heater is disposed in a polymerbody coupled to the lower surface of the dielectric body.
 15. Thesubstrate support assembly of claim 9, further comprising: a coolingplate coupled to the substrate support.
 16. A processing chambercomprising: a chamber body; a controller; and a substrate supportassembly, having an electrostatic chuck, the electrostatic chuck havinga dielectric body formed of a single coherent mass of ceramic material,the dielectric body comprising: an upper surface and a lower surface, achucking electrode disposed in the dielectric body, one or more mainresistive heaters disposed in the dielectric body, and a plurality ofsecondary heaters in the dielectric body between the main resistiveheaters and one of the upper surface and the lower surface, wherein aquantity of the secondary heaters is greater than a quantity of the mainresistive heaters, each secondary heater coupled to a unique powercircuit with the dielectric body, each power circuit configured toindependently operate the connected secondary heater between an on stateand an off state without changing the on state and off state of any ofthe other secondary heaters as well as the one or more main resistiveheaters.
 17. The processing chamber of claim 16, wherein any onesecondary heater is configured to remain in the off state whilesimultaneously switching all other secondary heaters to the on state.18. The processing chamber of claim 16, wherein the circuit furthercomprises: a plurality of individual state switches coupled to arespective secondary heater; and a control lead configured toindividually and directly each individual state switch to thecontroller, wherein the state switch modifies a power state for arespective secondary heater.
 19. The processing chamber of claim 18,wherein each state switch is disposed on a negative power lead of arespective secondary heater and is configured to selectively interruptthe flow of current across the negative power lead for powering therespective secondary heater.
 20. The processing chamber of claim 19,wherein the state switch is operable to allow 50% of the power to passthrough to the respectively connected secondary heater.